On a hot July day in 1941, gray-haired Adrian Grasseley sat at a small table in a room whose window overlooked Fifth Avenue, peering intently through a microscope at a large diamond.

Crowds strolled the streets below. Traffic rumbled along the Avenue. Pigeons sailed about the spires of St. Patrick’s Cathedral. Grasseley saw and heard none of this. All of his attention was concentrated on the diamond lying on the table before him—a fabulous stone the likes of which few men had ever seen.

This was the Vargas diamond, discovered two years earlier in Brazil. The stone weighed 726.6 carats. It was Grasseley’s job to divide it into twenty-three smaller stones which would be worth $2 million if he did his job well. The Vargas was one of the largest and most valuable diamonds ever to pass through Customs.

For forty years, Adrian Grasseley had cut, sawed and cleaved diamonds in Antwerp and in New York City. But this slender man with the thin, tapering fingers had never had the responsibility of splitting a Vargas. Few men ever had.

Diamond Merchant Harry Winston had purchased the stone for $700,000. He had turned it over to Grasseley to divide, and the cutter’s first important move would be to split the giant stone with a blow on the blade of a knife. If the diamond split smoothly, then the rest of the job would be relatively simple.

For weeks, hour after hour, Grasseley studied the Vargas, searching for the “grain” of the diamond. He looked for a hidden flaw which might cause the stone to burst into fragments, but he could find none.

At last Adrian Grasseley knew what had to be done. He would cut a small V-shaped notch at the precise point at which he intended to split the stone. Into this notch he would place a dull-edged knife. If his calculations were correct, a blow on the knife would cleave the diamond as truly as a piece of fine wood splits along its grain. If the blow were too heavy, or if he had misread the diamond’s structure, then the Vargas might shatter and a fortune would be lost.

On the night before the blow was to be struck, Grasseley did not feel any undue nervousness. His hands were steady and he congratulated himself on being relaxed. But he could not sleep. He turned and twisted in his bed, and he listened to the grandfather clock in the hallway toll the quarter hours.

“What is the matter with me?” he muttered irritably. “I am not nervous and I have not been worrying about the Vargas.” It was almost dawn before he dropped off to sleep.

The diamond cutter slept for only two hours. Then he hurried to the small room at Rockefeller Center where the diamond waited. All morning he worked to cut the small notch. He had lunch. And at 2 P.M. he was ready.